What information is kept in a linux file about the user and/or system that created it?

I want to make some files publicly available, posted on another server such as GitHub or FTP, but I'd rather the original user & system information not be included.

How can my intent be implemented?

  • "posted on another filesystem" Do you mean via NFS? Commented Aug 17, 2014 at 21:26
  • @DavidTonhofer Thank you for looking David Tonhofer! I mean another server such as GitHub or FTP.
    – user36556
    Commented Aug 17, 2014 at 21:27
  • 1
    For linux, there is nothing at the OS level which says anything about the system of origin or the user (there is no metadata, just a stream of bytes). But many file types do have such information, image files do, doc files do, PDF files do. You may want to take a look at exiftool and there are sure to be manuals about what to look out for example directly from the NSA: Hidden Data and Metadata in Adobe PDF Files: Publication Risks and Countermeasures. Maybe some other correspondent can give more info. Commented Aug 17, 2014 at 21:41
  • @DavidTonhofer Thank you David Tonhofer! So the original user ownership and group are not retained once moved to another server? Thank you again so much in advance!
    – user36556
    Commented Aug 17, 2014 at 23:38

1 Answer 1


The information you're talking about (UID, GID, timestamp, et.c) is stored in the file's inode. In UNIX systems, the inode is created whenever a file is created and it stores meta information about the file. When copying a file from system A to system B, a new file is created at B, thus a new inode is created for it. This inode now contains information about the file at system B, not about the file at system A. Both inodes can be completely different, depending under what user FTP was running, when it was uploaded, etc.

However, the file itself could contain sensitive information (like David Tonhofer mentioned), so make sure there's nothing like that.

  • (and don't forget about backup files - zip, tar, cpio etc)
    – symcbean
    Commented Aug 18, 2014 at 11:01

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